1. Field of the Invention
A machine frame for an elevator drive including a drive pulley and a deflecting roller. The deflecting roller may be variably positionable relative to the drive pulley. The position of the deflecting roller, relative to a drive pulley, may determine a spacing of carrying cables between the cage and the counterweight cables. Moreover, the deflecting roller position, with respect to the drive pulley, may influence a looping angle .beta. of the carrying cables on the drive pulley. The spacing between the carrying cables may be determined by a horizontal distance between the axes of the drive pulley and the deflecting roller plus their respective radii. The looping angle .beta. may be varied, within certain limits, by variably raising or lowering the arrangement of the deflecting roller relative to the drive pulley.
The above-noted features may be adapted to the individual requirements of construction and arrangement of the drive pulley and the deflecting roller in a machine frame which may depend on, e.g., cage size and nominal load. Thus, a number of arrangement variations may be contemplated depending on specific elevator models in use. Thus, by a single, substantially universally adaptable construction, the present invention may be utilized in a greater range of elevator systems than those in the prior art.
2. Discussion of Background Information
German published specification No. 1 033 383 discloses a simple drive unit for small-load elevators. This unit includes a drive pulley axle carrying a drive pulley and a belt pulley and arranged somewhat eccentrically at a horizontal profile beam. The belt pulley is arranged in driving connection with a motor including a small belt wheel and fastened while suspended below the profile beam. In addition, a pivotable rocker is arranged on the drive pulley axle and at its other end is provided a deflecting roller. The spacing between the carrying cables leading off can be varied within certain limits by the pivotable rocker which is retained in a desired position by a screwed-on vertical stay. Accordingly, the looping angle .beta. changes constrainedly and uninfluenceably. This may potentially negatively influence driving capability. Further, since the above-noted simple drive unit does not meet the applicable safety regulations, the unit is generally not suitable for passenger elevators without significant construction and accessory device modifications.